The Associated Press reports: "About 100 [Ukrainian] soldiers emerged triumphant from the previously rebel-occupied buildings, shouting the name of their battalion, Azov, and singing the Ukrainian national anthem. They also destroyed an armored vehicle and a heavy truck used by the separatists, leaving the vehicles scorched and riddled with large-caliber bullet holes."

Ukraine's Interior Minister Arsen Avakov said on his Facebook page that "All the key strongholds of terrorists at this time [have been] brought under control. [We] ... destroyed sniper [nests] of terrorists, killing some of them."

"The operation continues," he says.

Andrei Klochenok, a 37-year-old resident and steelworker in the city, said in a telephone interview with The Los Angeles Times that he and his wife "knew something was going on when the [pro-Russia] self-defense militants were very actively fortifying their barricades in town and installing large-caliber machine guns on some roofs and at some intersections the night before."

"The shooting in the morning was so intense that my wife and I were afraid to even approach the windows, which were shaking with explosions outside," he said.

"Five pro-Russian rebels were reported killed and four government soldiers injured in the city in Donetsk region.

"Hundreds of combatants and civilians have been killed since pro-Russian separatists in the Donetsk and neighbouring Luhansk regions declared independence after holding referendums last month, which were deemed illegal by the government in Kiev.

"The rebellion began after February's ousting of the elected President, Viktor Yanukovych, whose last-minute decision not to sign a landmark treaty with the EU in November sparked mass protests in Kiev."

The fighting follows reports on Thursday that Russian tanks had entered the fight on the side of the separatists.

The AP reports:

"Denis Pushilin, a leader of the separatist Donetsk People's Republic, told Russian state television Friday that they had the tanks but it was 'improper to ask' where they had gotten them.

" 'They are in Donetsk and are the minimum that we have to defend the city,' he said.

"Both the U.S. State Department and NATO have said if the tanks did come from Russia, it would be a 'serious escalation' of the crisis.

"Pushilin repeated the separatists' call for Russia to send peacekeeping troops into eastern Ukraine. Russia has said this could only be done with U.N. authorization."